1. Field of Invention
The present invention relates to a monkey wrench and, more particularly, to a one-way monkey wrench that is low in cost and easy in operation.
2. Related Prior Art
Fasteners such as threaded bolts and nuts are tightened and loosened by wrenches such as open-ended wrenches, box-ended wrenches, monkey wrenches one-way wrenches and socket wrenches.
A user can use a monkey wrench to drive fasteners of various sizes. In operation, the user engages the monkey wrench with a fastener, drives the fastener for an angle, and disengages the wrench from the fastener. The user may have to repeat this process for many times before the completion of the operation.
Alternatively, a user may use a one-way wrench to drive a fastener. In operation, the user engages a one-way wrench with a fastener, pivots the wrench in a direction so as to drive the fastener, and pivots the wrench in an opposite direction so as not to drive the fastener. The user does not have to repeat engagement and disengagement. However, the user has to use one-way wrenches of different sizes to drive fasteners of different sizes.
There have been one-way monkey wrenches such as those disclosed in Taiwanese Patent nos. 395311, 453253 and 566273. Two major problems have been encountered in the manufacturing and use of these one-way monkey wrenches. Firstly, their manufacturing is difficult since many parts are made and assembled into sophisticated structures. Secondly, their operation is not precise since they often slide on fasteners.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.